In fact, the most likely (and I do not presume to have the final world on this) candidate for the seminal event of 1960–1964 is Kennedy’s commitment of troops to Vietnam. From this flowed a tremendous amount of history, and not just the further commitments of LBJ and the subsequent social upheaval in the US. If the officers I talked to in the late Soviet period are correct, the Vietnam War bankrupted the Soviet Union. The Soviets spent approximately $1 billion per year in a war it truly could not afford:
“The Soviet Union poured billions of rubles into Vietnam… During 1965-1975 military aid was central, and economic aid was geared entirely to the war effort. By the 1970s Soviet aid amounted to $1 billion or more annually, without which the Democratic Republic of Vietnam (DRV) could not have continued the war.”
The adventure in Vietnam and the attendant arms race crippled the economy of the USSR. It severely curtailed their foreign policy adventures. And when Reagan came along and proposed Star Wars, Gorbachev threw in the towel. Not because he thought that the American missile shield would achieve 100% coverage against missile attacks. The Russians were not stupid. And not because they thought we’d even get 75% coverage. It was because even 30% coverage was considerably better than the 0% the Soviets could muster in the near term. And because it would have sapped a couple of percent of our GDP, while even attempting to match it would have cost a significantly grater fraction of their GDP (some officers I talked to estimated as much as 50%). And the US technology would have gotten better with time and experience, which would have sapped even more Russian resources. In this respect, the events of 1989 and 1991 were a direct result of Kennedy’s decision to commit to Vietnam and Reagan’s willingness to capitalize on the advantage gained by bankrupting the USSR and sending it into the period the Russians call “The Stagnation”.